2.5 million people in the U.S. have cardiac arrhythmias that cannot be controlled with traditional treatments. Ablation is one treatment for cardiac arrhythmias. Ablation destroys tissue that triggers or supports abnormal electrical pathways in tissue. Cardiac ablation attempts to target and eradicate the tissue of the abnormal electrical pathway, while avoiding normal tissue. Conventional ablation techniques use low-resolution images acquired by fluoroscopy or static images from computed tomography merged onto fluoroscopy. These techniques monitor the ablation by measuring tissue temperature, impedance at the surface of the tissue, and other indirect methods. Indirect methods of monitoring the ablation may result in delivering more lesions than necessary and prolonging procedure times. Traditionally, directly visualizing critical intra-cardiac structures in the heart when performing ablation was not feasible.